Background/aim: The incidence of cat allergies in children has increased over the years. Children with cat allergies have mostly reported respiratory symptoms. The skin prick test (SPT) is the most preferred method to demonstrate sensitization to allergens. However, not all children who develop cat sensitization due to environmental exposure become allergic to cats. In our study, we aimed to determine the frequency of sensitization to cat and cat allergy, cat-related symptoms, and the cut-off value for the SPT that may indicate cat allergy. Materials and methods: Patients aged 2-18 years, who applied to the Health Sciences University İzmir Dr Behçet Uz Pediatrics and Surgery Training and Research Hospital and Balıkesir University Application and Research Hospital Pediatric Allergy outpatient clinics between January 01, 2019 and December 31, 2020, were included in the study. Patients who underwent SPT and found to be sensitized to cat allergen, were evaluated retrospectively. Clinical and laboratory findings of the patients were recorded. Receiver operating characteristics (ROC) analysis was performed to determine the cut-off value for the SPT. Results: Sensitization to cat was detected in 140 (4%) out of 3499 patients who underwent SPT. The median age of the patients was 12 years (min-max: 5-18) and 67.1% were male. Eighty-eight (62.9%) patients were symptomatic upon contact with cats, predominantly with nasal symptoms. These patients had significantly larger cat SPT wheal size than asymptomatic patients. The cut-off value was determined as 5.5 mm with a sensitivity of 72.7% and a specificity of 61.5% (95% CI, 60.5%-78.4%). Symptoms resolved in about half of our patients by reducing contact with cats. Conclusion: The present study is the first to report the frequency and clinical findings of cat sensitizations and allergies in Turkish children. For effective treatment, cat allergy must be diagnosed. In this regard, the use of a practical, readily accessible 5.5 mm cut-off point on the SPT may be helpful.

Acute asthma exacerbations (AAE) are episodes characterized by potentially life-threatening and rapidly deteriorating asthma symptoms. Viral respiratory infections are one of the major triggers in the pathophysiology of childhood asthma exacerbations. In this study, we aimed to determine the distribution of viral agents among pediatric AAE patients. One hundred and three AAE patients, aged 5 or older, hospitalized between from February 2017 through February 2020 at Pediatric Immunology and Allergic Diseases Unit were included in this study. Fifty patients (48.5%) were female, and the mean age of the patients was 108.2 months. Viruses were detected in 58 (%56.3) of the patients, in 5 of whom more than one virus type was detected. The most commonly detected virus was human rhinovirus (n=43, 67.1%). Other types included respiratory syncytial virus (n=8; 12.5%), influenza (n=6; 9.3%), human metapneumovirus (n=4; 6.2%), adenovirus (n=1; 1.5%), enterovirus (n=1; 1.5%), and parainfluenza (n=1; 1.5%). Viral agents were detected in 29 out of the 47 patients with allergic asthma, with human rhinoviruses comprising the majority (18 patients). The mean length of hospital stay was 7.89 days. Human rhinovirus is the most common virus that triggers AAE, with similar distributions in allergic and non-allergic asthma. We found no correlation between virus type and the length of hospital stay.

Objective: In a large group of patients with primary immunodeficiency (PID), immunoglobulin replacement therapy is critical for infection control. There are two main methods of immunoglobulin replacement intravenous (IVIG) and subcutaneous (SCIG). The aim of this study was to determine the efficacy of SCIG by comparing IgG levels and frequency of infections obtained during SCIG replacements in patients with PID with those obtained during IVIG administration. Method: Immunoglobulin levels of 28 patients who were followed up in our clinic with a diagnosis of PID and who started IVIG replacement and switched to SCIG replacement after follow-up, were evaluated retrospectively. Serum IgG levels and frequency of infections before starting immunoglobulin treatment, the previous year of IVIG before starting SCIG replacement, and during the first six months, second six months, and second year of SCIG replacement were compared. Results: The mean age of all the patients that received SCIG was 10.5 years (min 15 months, max 23 years) and eleven of the patients were female. The mean serum IgG level of the patients before starting immunoglobulin replacement was 701±383 mg/dl, and for the final year they received IVIG replacement before switching to SCIG replacement it was calculated to be 900±342 mg/dl. The mean value was found to be 1082±312 mg/dl in the first six months after the initiation of SCIG, 1102±287 mg/dl in the second six months, and 1145±311 mg/dl in the second year. Serum IgG levels of the patients were significantly higher during IVIG and SCIG replacement than before treatment (p<0.05). Serum IgG levels during the first six months, second six months, and second year of SCIG treatment were significantly higher than levels during IVIG treatment (p=0.000, p=0.003, and p=0.002, respectively). Conclusion: Compared to IVIG replacement, significantly higher and more stable serum IgG levels can be obtained with SCIG replacement. This is expected to ensure improved outcomes in the management of infections in PID patients.

Background/Objectives: Obesity may alter the prognostic value of biomarkers in childhood asthma. We examined whether transforming growth factor beta 1 (TGF-β1), soluble suppression of tumorigenicity 2 (sST2), C-X-C motif chemokine ligand 8 (CXCL8), and insulin-like growth factor 1 (IGF-1) were associated with sustained treatment escalation and whether associations differed by obesity status. Methods: The development cohort included 292 children: 90 non-atopic controls, 108 with normal-weight asthma, and 94 with obese asthma; longitudinal analyses included 202 with asthma. Biomarkers were modeled continuously in prespecified Cox models with biomarker-by-obesity interactions, internally validated with 1000 bootstrap resamples, and applied without refitting or recalibration to an independent Van cohort of 180 children with asthma. Results: Seventy-five children experienced sustained treatment escalation. TGF-β1 was associated with escalation in obese asthma (hazard ratio [HR] per 500 pg/mL, 2.12; 95% confidence interval [CI], 1.66–2.70; interaction q < 0.001), whereas CXCL8 was associated with escalation in normal-weight asthma (HR per 10 pg/mL, 2.06; 95% CI, 1.67–2.54; interaction q < 0.001). Adding TGF-β1 or CXCL8 increased 12-month time-dependent area under the curve (AUC) from 0.623 to 0.732 and 0.746. In Van, AUCs were 0.751 and 0.744, and interactions remained significant after adjustment (q = 0.036). sST2 showed a weaker obesity-related signal, whereas IGF-1 added little prognostic information. Conclusions: Prognostic biomarker associations differed by obesity status. TGF-β1 was associated with escalation in obese asthma, whereas CXCL8 was associated with escalation in normal-weight asthma. Further validation is needed before clinical use.

Objective: The aim of this study was determine the rate of confirmed drug allergy using a stepwise diagnostic algorithm in children with a suspected or previously labeled drug allergy, to assess the proportion of patients in whom an incorrect drug-allergy label could be safely removed (delabeling rate), and to evaluate the diagnostic tests applied. Materials and Methods: In this retrospective cross-sectional study, children presenting with suspected drug allergy to our pediatric allergy clinic between April 2023 and January 2025 were evaluated retrospectively. A stepwise protocol comprising detailed history, drug-specific IgE, skin tests (prick and intradermal), and drug provocation testing (oral or, when clinically indicated, subcutaneous or intravenous) was applied. Of 127 patients initially assessed, 41 were excluded and 86 who completed the clinically indicated diagnostic evaluation were analyzed. Results: The mean age was 10.5±4.6 years. True drug allergy was confirmed in 16 patients (18.6%), whereas the incorrect drug-allergy label was safely removed in 70 (81.4%). Beta-lactams were the most common culprit group (12/16; 75.0%). Parental atopy, parental drug allergy, and personal atopy were significantly more frequent in the true-allergy group (p=0.004, p=0.028, and p=0.006, respectively), whereas no significant difference was found for age, sex, or laboratory parameters. In 10 confirmed patients, the diagnosis was established only by OPT. Anaphylaxis occurred in two of the 74 OPTs performed (2.7% per test). Conclusion: In the majority of children presenting with suspected drug allergy, true allergy can be safely excluded through comprehensive diagnostic evaluation. Under appropriate patient selection and safe conditions, OPT is the gold-standard method for confirming or excluding true drug allergy, while specific IgE and skin tests support a stepwise evaluation for selected drugs; referral of these children to a pediatric allergist is important for both individual patient safety and antimicrobial stewardship.

Objective: Hereditary Angioedema (HAE) is a rare but life-threatening disease. It is aimed to present data on the clinical characteristics of our pediatric patients with HAE, whose symptoms usually start in childhood, but the delay in diagnosis is still a serious problem. Method: Clinical and laboratory findings, family histories, and clinical characteristics of 14 patients with HAE diagnosed in our clinic between 1998-2019 were analyzed. Results: Half of our patients diagnosed with HAE were girls, 78.5% of them were diagnosed with HAE type 1, and 21.4% were HAE type 2. All our patients had a family history, and 10 of them were diagnosed based on their family history. The mean age at diagnosis was 9.7±4.4 years and the mean age at the onset of the first angioedema symptom was 5.3±1.8 years. The delay in diagnosis was 4.4±4.1 years. The swollen areas included extremities (78.5%), abdominal attacks (71.4%), facial edema (57.1%), and laryngeal edema (21.4%). C4 levels were low in all patients. The mean C1 esterase inhibitor level was 0.69±0.08 g/l for HAE type 2 and 0.08±0.04 g/l for HAE type 1. The mean C1 esterase inhibitor functional activity level was 18.6±10.4% in HAE type 2. Conclusion: Early diagnosis of the disease is critical for reducing morbidity and mortality due to attacks. There are very few studies in Türkiye that focus exclusively on pediatric HAE patients. Sharing our patients’ clinical findings and treatment plans for this rare disease is crucial for bringing the disease to light and raising awareness.